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Dynaco Pas 4
21 Reviews
rating  4.76 of 5
MSRP  1000.00
Description: Modern tube preamplifier


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Reviews 1 - 5 (21 Reviews Total) | Next 15

User Reviews

Overall Rating:5
Value Rating:5
Submitted by Robert C. a AudioPhile

Date Reviewed: July 10, 2015

Bottom Line:   
I've been using PAS-4 for about 18 years. Never failed me.
As far as sound quality is concerned this pre is a champ. But few things have to be done:
1. Replace cheap power cord with a good one. I did that and little hum it had was almost gone.
2. Replace stock vacuum tubes with good quality tubes. It's an investment of about $130.00 but it's worth all the money.
After light modification this preamp will reward you with airy mids, good micro/macro dynamics, good treble extension, springy bass, decent sound stage and imaging. This what mine did to me after tubes and cord replacement.
With good recording (CD or LP) PAS-4 shows a good deal of "being there" impression. CDs definitely sound better. I stress it again, replacing stock tubes is really important if you want to have a good sound. It has some shortcomings but comparing it to my ARAGON AURUM pre amp ($1900 when new) left me scratching my head which one to choose. It's that good. It's definitely more airy than AURUM.
If you can find used one in a good condition do not hesitate to buy it.
Who knows, buying PAS-4 might be the beginning of the addiction to tubes and tube sound.
No, I'm not going to sell mine. Phono stage is too good.

Associated equipment:
ARAGON 8008ST - amp
VPI Scout Jr - turn table
Denon 1650 - cdp
PS Audio DAC III - digital to analog converter
Legacy Classic HD - speakers
AudioQuest, Nordost, Alpha-Core (Goertz) - cables

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Used product for:   More than 1 year

Duration Product Used:   AudioPhile

Product model year:   1997



Overall Rating:5
Value Rating:5
Submitted by Ralph Perrini a AudioPhile

Date Reviewed: March 16, 2012

Bottom Line:   
I urchased this PAS-4 new from J & R Music World back in March 1997 for $ 500.00 exactly 15 years ago. The unit has been making beautiful music in my system since then. The fit and finish is very good, and the innards are neat and well made. One of my very best audio purchases ever!

Replacing the original 6922 tubes in the linestage with 6N1Ps made a big improvement, as did replacing the stock power cord. The 6N1Ps are not only quieter, with their slightly lower gain they give the volume control a much greater useful range, with the 6922 things got very loud with the volume control at 9 o'clock. I don't use the phono stage since I have an outboard phono stage for my low output MC cartridge. However I had to leave the phono tubes in because removing them produced an infernal howl.

The combination of this pre-amp with my solid state Acurus A100, also purchased 15 years ago produces a very detailed, smooth sound that holds up well against far more expensive set ups. And having served reliably in my system for 15 years and counting I can vouch for it's quality and reliably. If you can get your hands on one I highly recommend it.

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Used product for:   More than 1 year

Duration Product Used:   AudioPhile

Product model year:   1997



Overall Rating:5
Value Rating:5
Submitted by rgf343 a AudioPhile

Date Reviewed: January 25, 2005

Bottom Line:   
Have tried quite a few preamps., both S.S. and tube, e.g. Audio Research and B.A.T.. The PAS-4 is a well designed and built preamp. that sounds great as is. However, get rid of the 6922s in the line section, replace with a matched pair of Russian 6N1Ps, Cyro treated, from Tubeman, and, if you don't use LPs, take the phono tubes (12ax7s & 6922s) out of the low level section (unit will run cooler). Most preamps. won't allow use of 6N1Ps to replace 6922s because of increased filament current needed, however the PAS4s regulated power supply handles this without difficulty. Upgrade the power cable to 16 ga., polish the chassis (so it will go faster and look impressive), let unit warm up for a couple of hours and you will experience a preamp. that will definately blow your hair back, assuming you have good equipment to utilize with it. Sound is extremely clear, distortion is reduced, low frequency transients and ability to access frequencies in the bottom octave with absolute authority, along with smooth, extended high frequency output is nothing short of phenominal. Dynamic range is outstanding. In my opinion it would take a class of preamps. costing several thousands just to match what this is capable of with these minor changes, don't forget to polish the chassis for reduced wind resistance. If you can locate one my advice is grab it when you can, hopefully you will be as pleased as I am. rgflato3@hotmail.com

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Used product for:   1 to 3 months

Duration Product Used:   AudioPhile

Product model year:   1995

Price Paid:    $425.00

Purchased At:   eBay



Overall Rating:5
Value Rating:5
Submitted by JohnJE a AudioPhile

Date Reviewed: April 6, 2003

Bottom Line:   
Had a Superphon pre for 14 years - wondered what I was missing in tube pre's. Bought a vintage PAS-3 - tho lacking alot, the midrange was alluring.

Not wanting to spend much $$, I found the great reviews here at AudioReview to be convincing.

Found SoundBug1 on ebay, bought a retubed B stock PAS-4 for $599.00 (Tel 12ax7's in phono and chrome knobs).

Tell ya' what..I've heard many other tube units in past year or so and the PAS-4 is good enough to stand on its own against any I've heard.

The Russian Sovvies are good..I upgraded to Russian Military Rocket 6H23. Clearer, smoother - a little less dynamic. The Sovtek 12ax7LPS are as good as any - save your money on pricey NOS tubes. Hook the rig up to good filtering (mine thru PS Audio PP300 and Ultimate Outlet)and upgraded cord (real benefits)and distance with megabuck units becomes quite small.

Tho it's called a Tube preamp, buffering makes it more dynamic and less euphonic than all tube units. In reality, it's a hybrid unit rather than all tube. Makes it better to my ears.

Put it on good stand/isolation, sorbothane or akin equipment points, give it air to breathe and your a happy dude with the music.

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Used product for:   More than 1 year

Duration Product Used:   AudioPhile

Price Paid:    $599.00

Purchased At:   soundbug1@aol.com



Overall Rating:5
Value Rating:4
Submitted by Vincent Chen a AudioPhile

Date Reviewed: September 19, 2002

Bottom Line:   
Smoothness,finess, and good detail are what I like about this used Preamp I bought. I haven't changed tubes yet but soon to be done. Well currently I am using a Sony XA7ES CD player for the front end, Sonic Frontiers SFM-75 Tube Mono Blocks with KEF C80 speakers. I listen to a wide mix of music, except "RAP". This preamp even made my Rotel RMB-1095 sound more fluid without that hard edgy Transistor sound. My main focus was to build a Tube based system for less than $2000.00. Sure the Dyna is not perfect, I like the C.J. preamps better for detail, refined harmonics etc. but have you checked new C.J. prices
lately? The Dyna Pas 4 then is a terrific bargain. I love it on female vocals, and Solo Acoustic Jazz Instruments best. I always wanted a Dyna kit to build, but missed out on that, so I guess this is the next best thing. I almost bought a Bottlehead Preamp kit. I hear they are great, but the lazy person in me made the Pas 4 the only choice. Musically satisfying, and affordable, and terrific way to take the edge off CD and Solid State. Try one out and see if it is right for you. It was for me. Highly Recommended BARGAIN.

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Used product for:   Less than 1 month

Duration Product Used:   AudioPhile

Product model year:   1996

Price Paid:    $350.00

Purchased At:   JMSOUND




Reviews 1 - 5 (21 Reviews Total) | Next 15

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